Terpolymer compositions for coating substrates used in computer printers

ABSTRACT

Terpolymer compositions of vinyl caprolactam (VCL), dimethylaminopropyl methacrylamide (DMAPMA) and hydroxyethyl methacrylate (HEMA) are described to coat substrates for use in computer printers, and provide advantageous print quality thereon.

CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATIONS

This application is a divisional of application Ser. No. 10/926,519,filed Aug. 26, 2004, now U.S. Pat. No. 6,939,934 which is acontinuation-in-part of U.S. patent applications, Ser. No. 10/388,697,filed Mar. 14, 2003, now U.S. Pat. No. 6,872,787, and Ser. No.10/153,411, filed May 22, 2002, now U.S. Pat. No. 6,806,310, allassigned to the same assignee as herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to polymer compositions used to coat substratessuch as paper for use in computer printers, and, more particularly, toterpolymer compositions which provide advantageous light stability fordyes used in inkjet printers.

2. Description of the Prior Art

The advent of color inkjet printing has been instrumental in fueling theprint-on-demand revolution and has also created a number of challenges.Often, the surface of the desired media does not possess the necessaryproperties for accepting the ink-jet ink. This results in long dry timesand/or a poor ink-jet image or light stability. It has long beenrecognized that a surface treatment or media coating plays a criticalrole in the final print quality. Numerous media coatings are known inthe art. They may contain any number of components and often consist ofmore than one layer.

Accordingly, it is an object of this invention to provide a terpolymercomposition which is particularly suitable for use in surface treating asubstrate such as paper, polyester and vinyl plastics, canvas and thelike, used in digital printing.

SUMMARY OF THE INVENTION

What is described herein is a terpolymer composition of vinylcaprolactam (VCL), dimethylaminopropyl methacrylamide (DMAPMA) andhydroxyethyl methacrylate (HEMA), uncrosslinked or crosslinked,unquaternized or quaternized, preferably crosslinked and quaternized,and a water or water/alcohol solution of the terpolymer, e.g. awater/alcohol solution of 20-40% solids of the terpolymer, preferably25-35% solids of the terpolymer, having a viscosity of 3,000 to 25,000cps (LV#4, 12 rpm, 25° C., 30% solids).

In other embodiments of the invention the terpolymer is present in theform of a powder.

Suitably, the terpolymer composition of the invention comprises, by wt.,60-90% VCL, 10-30% DMAPMA and 2-10% HEMA, preferably 75-80% VCL, 13-16%DMAPMA and 4-6% HEMA.

In other aspects of the invention, the terpolymer composition includesup to about 0.8% of a crosslinking agent, and up to 40% of aquaternizing agent.

Suitable crosslinking agents include pentaerythriol triallyl ether(PETE); pentaerythriol tetraacrylate (PETA).

Suitable quaternizing agents include HCl and H₂SO₄.

Preferably the crosslinking agent is present in an amount of 0.5-0.7%;and the quaternizing agent in an amount of 2.5-3.5%, by wt. of theterpolymer.

The invention therein includes a process of making the terpolymercomposition described above which comprises the steps of polymerizingthe monomers in an aqueous-alcohol solvent, suitably wherein the alcoholis ethanol or isopropyl alcohol, at about 20-40% solids, in the presenceor absence of a crosslinking agent, thereafter, if desired, quaternizingthe product, removing the alcohol solvent to provide a water onlysolution of the terpolymer, and drying to provide the terpolymer in theform of a powder.

The invention also includes use formulations of the terpolymer of theinvention, optionally with other water/alcohol-born ingredients, e.g.polyvinyl alcohol (PVA), latex, acrylate polymers, styrene-butadienelatex, cross-linkers, gelatin or a cellulosic ingredient.

The terpolymer may be post-treated, if desired, e.g. by heating with apost-treating crosslinking agent, to increase its viscosity or enhancethe water resistance of the dried film, as described in detail in theaforementioned U.S. patent applications. Suitable post-treatmentcrosslinkers described therein include polyepoxides, e.g. Ancarez AR550; melamine/formaldehyde resins, e.g. Berset 2003; and aziridines.

In commercial use for digital inkjet printing, a suitable substrate suchas paper, polyester or vinyl plastics, canvas and the like, is coatedwith he terpolymer of the invention to render the coated substrate morereceptive to inkjet printing. Such coated substrates exhibitparticularly advantageous light stability to dyes ordinarily present ininkjet-printers.

The invention will be described in more detail by reference to thefollowing examples in which:

EXAMPLE 1 VCL/DMAPMA/HEMA/PETE/HCL in Water/ETOH

-   1. Set up 1.0 l autoclave reactor fitted with anchor type agitator,    thermocouple and nitrogen purging line.-   2. Charge the reactor initially with 79.83 g of DI water, 22.50 g of    ethanol SDA-40B, 240.00 g of 50/50 mixture of vinyl caprolactam and    ethanol, 0.9240 g of PETE.-   3. Pressurize the reaction mixture with nitrogen for 3 times at 60    psig and hold it for 2 minutes and release it, leave the pressure to    about 10 psig during reaction.-   4. Heat it to 80° C., during which take 22.50 g of DMAPMA, 7.50 g of    HEMA mixed with 107.5 g of DI water and purge it with nitrogen for    15 minutes and then charge to the pump.-   5. At 80° C., charge 26.99 ml of DMAPMA/HEMA/water mixture by using    pump in 5 minutes.-   6. Then set time=0 minutes, add first shot of Vazo-67 by mixing    0.3542 g of Vazo-67 with 1.2500 g of ethanol SDA 40B, and also start    continuous addition of DMAPMA/water for 360 minutes at the flow rate    of 0.310 ml/min.-   7. Add another shots of Vazo-67 by mixing 0.3542 g of Vazo-67 with    1.2500 g of ethanol SDA 40B at 60, 180, 300, 420, 600 and 840    minutes. [Total 7 shots of Vazo-67].-   8. Hold the reaction for two more hours after final shot of Vazo-67    and check residual VCL at 960 minutes, if VCL is higher than 2000    ppm then add one more shots of Vazo-67 and hold for two more hours    or else, cool down the reaction to 40° C.-   9. Then neutralize the batch with conc. HCl. The final pH should be    in the range of 6.5 to 7.5.-   10. Filter it through Millipore filter tube using 41μ screen.

EXAMPLE 2 VCL/DMAPMA/HEMA/HCL in Water/ETOH

-   1. Set up 1.0 l autoclave reactor fitted with anchor type agitator,    thermocouple and nitrogen purging line.-   2. Charge the reactor initially with 79.83 g of DI water, 22.50 g of    ethanol SDA-40B, 240.00 g of 50/50 mixture of vinyl caprolactam and    ethanol.-   3. Pressurize the reaction mixture with nitrogen for 3 times at 60    psig and hold it for 2 minutes and release it, leave the pressure to    about 10 psig during reaction.-   4. Heat it to 80° C., during which take 22.50 g of DMAPMA, 7.50 g of    HEMA mixed with 107.5 g of DI water and purge it with nitrogen for    15 minutes and then charge to the pump.-   5. At 80° C., charge 26.99 ml of DMAPMA/HEMA/water mixture by using    pump in 5 minutes.-   6. Then set time=0 minutes, add first shot of Vazo-67 by mixing    0.3542 g of Vazo-67 With 1.2500 g of ethanol SDA 40B, and also start    continuous addition of DMAPMA/water for 360 minutes at the flow rate    of 0.310 ml/min.-   7. Add another shots of Vazo-67 by mixing 0.3542 g of Vazo-67 with    1.2500 g of ethanol SDA 40B at 60, 180, 300, 420, 600 and 840    minutes. [Total 7 shots of Vazo-67].-   8. Hold the reaction for two more hours after final shot of Vazo-67    and check residual VCL at 960 minutes, if VCL is higher than 2000    ppm then add one more shots of Vazo-67 and hold for two more hours    or else, cool down the reaction to 40° C.-   9. Then neutralize the batch with conc. HCl. The final pH should be    in the range of 6.5 to 7.5.-   10. Filter it through Millipore filter tube using 41μ screen.

EXAMPLE 3 VCL/DMAPMA/HEMA/PETE/HCL in Water

-   1. Set up 1.0 l autoclave reactor fitted with anchor type agitator,    thermocouple and nitrogen purging line.-   2. Charge the reactor initially with 79.83 g of DI water, 22.50 g of    ethanol SDA-40B, 240.00 g of 50/50 mixture of vinyl caprolactam and    ethanol, 0.9240 g of PETE.-   3. Pressurize the reaction mixture with nitrogen for 3 times at 60    psig and hold it for 2 minutes and release it, leave the pressure to    about 10 psig during reaction.-   4. Heat it to 80° C., during which take 22.50 g of DMAPMA, 7.50 g of    HEMA mixed with 107.5 g of DI water and purge it with nitrogen for    15 minutes and then charge to the pump.-   5. At 80° C., charge 26.99 ml of DMAPMA/HEMA/water mixture by using    pump in 5 minutes.-   6. Then set time=0 minutes, add first shot of Vazo-67 by mixing    0.3542 g of Vazo-67 with 1.2500 g of ethanol SDA 40B, and also start    continuous addition of DMAPMA/water for 360 minutes at the flow rate    of 0.310 ml/min.-   7. Add another shots of Vazo-67 by mixing 0.3542 g of Vazo-67 with    1.2500 g of ethanol SDA 40B at 60, 180, 300, 360, 480, 600 and 840    minutes. [Total 7 shots of Vazo-67].-   8. Hold the reaction for two more hours after final shot of Vazo-67    and check residual VCL at 960 minutes, if VCL is higher than 2000    ppm then add one more shots of Vazo-67 and hold for two more hours    or else, cool down the reaction to 40° C.-   9. Then neutralize the batch with conc. HCl. The final pH should be    in the range of 6.5 to 7.5.-   10. Distill off ethanol to replace with DI water using vacuum. %    Ethanol should be less than 5.0%, and adjust the final % solids to    30%.-   11. Add 0.85 g [0.17% of batch size of 500 g] of BTC-50NF as    preservative. Stir for 1.0 hour.-   12. Filter it through Millipore filter tube using 41μ screen.

EXAMPLE 4 VCL/DMAPMA/HEMA/HCL in Water

-   1. Set up 1.0 l autoclave reactor fitted with anchor type agitator,    thermocouple and nitrogen purging line.-   2. Charge the reactor initially with 79.83 g of DI water, 22.50 g of    ethanol SDA-40B, 240.00 g of 50/50 mixture of vinyl caprolactam and    ethanol.-   3. Pressurize the reaction mixture with nitrogen for 3 times at 60    psig and hold it for 2 minutes and release it, leave the pressure to    about 10 psig during reaction.-   4. Heat it to 80° C., during which take 22.50 g of DMAPMA, 7.50 g of    HEMA mixed with 107.5 g of DI water and purge it with nitrogen for    15 minutes and then charge to the pump.-   5. At 80° C., charge 26.99 ml of DMAPMA/HEMA/water mixture by using    pump in 5 minutes.-   6. Then set time=0 minutes, add first shot of Vazo-67 by mixing    0.3542 g of Vazo-67 with 1.2500 g of ethanol SDA 40B, and also start    continuous addition of DMAPMA/water for 360 minutes at the flow rate    of 0.310 ml/min.-   7. Add another shots of Vazo-67 by mixing 0.3542 g of Vazo-67 with    1.2500 g of ethanol SDA 40B at 60, 180, 300, 360, 480, 600 and 840    minutes. [Total 7 shots of Vazo-67].-   8. Hold the reaction for two more, hours after final shot of Vazo-67    and check residual VCL at 960 minutes, if VCL is higher than 2000    ppm then add one more shots of Vazo-67 and hold for two more hours    or else, cool down the reaction to 40° C.-   9. Then neutralize the batch with conc. HCl. The final pH should be    in the range of 6.5 to 7.5.-   10. Distill off ethanol to replace with DI water using vacuum. %    Ethanol should be less than 5.0%, and adjust the final % solids to    30%.-   11. Add 0.85 g [0.17% of batch size of 500 g] of BTC-50NF as    preservative. Stir for 1.0 hour.-   12. Filter it through Millipore filter tube using 41 μscreen.

EXAMPLE 5 Dye Color Stability for Composition

Test Pattern

The light fastness of the polymer was measured by applying a 10% solidssolution to polyester film using a #38 Meyer bar (film thickness ˜9micron). The film was then dried in oven and then a test pattern wasprinted using a HP 832C ink jet color printer.

Light Fastness (Color Stability to UV Light)

The test strip from the test pattern print was subjected to UV light for24 hours using an Atlas sun tester (ASTM G 53-84 test method). Theoptical density (using a Macbeth Densitometer) of the four colors aremeasured on the control and the treated strips and the percent fading isreported. Percent fading is the optical density of the color on theuntreated strip minus the optical density of the color on the treatedstrip divided by the optical density of the color on the untreatedstrip.

For PVP containing polymers (copolymers) the percent fading was above50%, whereas, for the VCL polymers (terpolymers) the percent fading wasless than 25%.

EXAMPLE 6 Powders of Terpolymer Compositions of Invention

The aqueous terpolymer compositions of Examples 3 and 4 were dried usinga drum dryer, a freeze dryer, a belt dryer, or by spray drying, toprovide the terpolymer composition in the form of a powder.

EXAMPLE 7 Inkjet Printable Coating #1

-   1. Add 294 g of water to a 1-L beaker. Adjust pH to 9-10 with sodium    hydroxide (Aldrich).-   2. Add 20.9 g of barium sulfate (Aldrich).-   3. Add 20.9 g of Engelhard Disintex 1000.-   4. Add 20.9 g of Millennium Chemicals Silcron G100 silica.    Homogenize and mix thoroughly.-   5. Add 10 g of Dow UCAR Latex 313 while mixing.-   6. Add 53 g of VCL/DMAPMA/HEMA/PETE/HCl (30% solids) while mixing.-   7. Add 9 g of Air Products Ancarez AR 550. Homogenize and mix    thoroughly.

Coat on substrate such as polyester, canvas or paper with #40 Meyer rod,and dry in air oven at 135° C. Print on HP 880C in Premium Photo PaperMode. Improved light stable, water resistive prints are achieved.

EXAMPLE 8 Inkjet Printable Coating #2

-   1. Add 56.9 g of water to 200 mL beaker.-   2. Add 39 g of ISP/PCI Aquazol 200 (9.2% solids).-   3. Add 17 g of VCL/DMAPMA/HEMA/PETE/HCl (30% solids).-   4. Add 0.1 g of ISP Easy Sperse.-   5. Add 0.2 g of Eastman CP 349W.-   6. Add 1 g of concentrated ammonium hydroxide. Continue to adjust pH    until pH ˜9 to 10.-   7. Add 0.3 g Bayer XAMA-7.

Coat on substrate such as polyester, vinyl or paper with #40 Meyer rod,and dry in air oven. Print on HP 880C in Premium Photo Paper Mode. Lightstable prints are achieved.

EXAMPLE 9 Inkjet Printable Coating #3

-   1. Add 40 g of water to 200 mL beaker.-   2. Add 20 g of Aldrich 88% hydrolyzed polyvinyl alcohol (20%    solids).-   3. Add 22 g of VCL/DMAPMA/HEMA/PETE/HCl (30% solids).-   4. Add 0.3 g of Cytec Cycat 4040.-   5. Add 0.2 g of Bercen Berset 2003.

Coat on substrate such as polyester or paper with #40 Meyer rod, and dryin air oven at 135° C. Print on HP 880C in Premium Photo Paper Mode.Light stable prints are achieved.

EXAMPLE 10

The VCL/DMAPMA/HEMA/PETE/HCl terpolymer are used in conjunction withacrylic polymers, acrylic copolymers, alginates, cross-linkers,carrageenan, microcrystalline cellulose, gelatin, carboxymethylcellulosesodium, hydroxyethylcellulose, hydroxypropylcellulose,hydroxypropylmethylcellulose, methylcellulose, guar and guarderivatives, locust bean gum, organoclays, polyethylene oxide,polyvinylpyrrolidones, copolymers of polyvinylpyrrolidones, silica,aluminates, zirconates, calcium carbonates, water-swellable clay,xanthan gum and pigments (inorganic) to achieve advantageous inkjetprintable surface coatings having light stability.

While the invention has been described with particular reference tocertain embodiments thereof, it will be understood that changes andmodifications may be made which are within the skill of the art.Accordingly, it is intended to be bound only by the following claims, inwhich:

1. A formulation including a terpolymer composition consistingessentially of vinyl caprolactam (VCL), dimethylaminopropylmethacrylamide (DMAPMA) and hydroxyethyl methacrylate (HEMA),uncrosslinked or crosslinked, unquaternized or quaternized, whichexhibits light stability to dyes found in ink-jet printers, as evidencedby a less than 25% color fading in the ASTM G-53-84 test.
 2. Aformulation according to claim 1 which includes another water solubleingredient.
 3. A formulation according to claim 2 wherein saidingredient is polyvinylalcohol (PVA), polyvinylpyrrolidone, acrylate,styrene-butadiene latex, gelatin, poly(2-ethyl-2-oxazoline), and/or acellulosic polymer.
 4. A formulation according to claim 2 wherein saidingredient is an inorganic pigment selected from a silicate, aluminate,zirconate, barium sulfate, calcium carbonate and clay.
 5. A formulationaccording to claim 1 wherein the terpolymer is uncrosslinked.
 6. Aformulation according to claim 1 wherein the terpolymer is crosslinked.7. A formulation according to claim 1 wherein the terpolymer isunquaternized.
 8. A formulation according to claim 1 wherein theterpolymer is quaternized.
 9. A formulation according to claim 1 whereinthe terpolymer is crosslinked and quaternized.
 10. A formulationaccording to claim 1 wherein the terpolymer composition comprises bywt., 60-90% VCL, 10-30% DMAPMA and 2-10% HEMA.
 11. A formulationaccording to claim 10 wherein the terpolymer composition comprises bywt., 75-80% VCL, 13-16% DMAPMA and 4-6% HEMA.
 12. A formulationaccording to claim 10 wherein the terpolymer composition includes up toabout 0.8% of a crosslinking agent.
 13. A formulation according to claim10 wherein the terpolymer composition comprises up to 40% of aquaternizing agent.
 14. A formulation according to claim 10 wherein theterpolymer composition comprises a crosslinking agent and thecrosslinking agent is pentaerythriol triallyl ether (PETE).
 15. Aformulation according to claim 10 wherein the terpolymer compositioncomprises a crosslinking agent present in an amount of 0.5-0.7% by wt.of the terpolymer.